Insulated non-halogenated heavy metal free vehicular cable

ABSTRACT

Described is an insulated non-halogenated, heavy metal free vehicular cable comprising an inner core of a copper based metal wire having a cross sectional area of at least about 0.1 mm 2 , and an outer insulation, covering the length of the inner core, comprised of a thermoplastic polyphenylene ether composition that has no halogen or heavy metal added thereto, the insulated cable capable of meeting the testing standard ISO 6722.

TECHNICAL FIELD

The present invention is concerned with a vehicular cable that utilizes insulation that is non-halogenated and heavy metal free. In particular, the invention pertains to an automotive wire harness of a non-halogenated composition.

BACKGROUND OF THE INVENTION

Environmental regulations dictate that the material selection in the vehicular industry needs to be halogen free and heavy metal free compositions especially for the vehicular cables. Typically, polyvinyl chloride (PVC) is utilized because of its combination of competitive raw materials costs and desirable properties. These properties include processibility, toughness, chemical resistance and ability to withstand temperatures typical for many applications in automotive environments.

Unfortunately, the chlorine content of PVC limits its disposal at the end of the life of the vehicle. Also there are concerns about effects on health and the environment by PVC by-products and PVC plasticizer. Accordingly, therefore, a replacement for PVC has long been sought with an intent to find competitive cost efficient replacements. In addition, performance must be taken into account including high temperature endurance, toughness processability and also reduction in weight.

It is therefore desirable to have a material that is a vehicular cable insulation, is cost effective and still achieves desirable characteristics such as lack of halogens and heavy metals, appropriate conductivity, temperature resistance, scrape abrasion resistance, resistance to heat aging, resistance to automotive fluids and resistance to flame and in particular to be capable of meeting the standard ISO (International Organization for Standardization) 6722 and offers all these properties with a reduction in weight.

SUMMARY OF THE INVENTION

Described is an insulated non-halogenated, heavy metal free vehicular cable comprising an inner core of a copper based metal wire having a cross sectional area of at least about 0.1 mm², and an outer insulation, covering the length of the inner core, comprised of a thermoplastic polyphenylene ether composition that has no halogen or heavy metal added thereto, the insulated cable capable of meeting the testing standard ISO 6722.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects and advantages of the invention will be apparent from the following description and appended claims, reference being made to the accompanying drawings forming a part of the specification, wherein like reference characters designate corresponding parts in several views.

FIG. 1 is a perspective view of the vehicular cable of the present invention;

FIG. 2 is a cross-section of FIG. 1 taken along lines 2-2;

FIG. 3 is a die used to manufacture an embodiment of the insulated vehicular cable of the present invention; and

FIG. 4 is a cross-section of FIG. 3 taken along lines 4-4.

DETAILED DESCRIPTION OF THE INVENTION

With increasing electronic content in automobiles there is an ever growing need for miniaturizing the size of the cables that provide resistance to physical abuse and provide resistance to flame and automotive fluids among other requirements to be met for the automotive industry such as Iso 6722. It has been found to be particularly desirable to utilize an insulated non-halogenated, heavy metal free vehicular cable containing a copper based metal wire that has a diameter of at least about 0.1 mm or more and an outer insulation covering the length of the inner core comprised of a thermoplastic polyphenylene ether composition which has no halogen or heavy metal added thereto.

DEFINITIONS

By “non-halogenated” is meant that the polymeric material that is utilized has no halogen material that is added to the composition, as a desirable component of the composition.

By “heavy metal free” is meant that no heavy metal such as mercury, hexavalent chrome, cadmium, lead and the like are added to the metal core, as a desirable component of the metal composition.

By “copper based metal” is meant that the metal wire is comprised of greater than 50% by weight of the metal being copper, or copper alloyed with other metal components as is well known in the industry yet maintaining suitable electrical conductivity. Well known copper based alloys may be used such as HPC-80EF, trademark Phelps Dodge.

By “polyphenylene ether” is meant a thermoplastic polymeric material which is commercially available and generally are polymers of monohydroxy aromatic-materials. Other readily available materials are 2, 6-xylenol or a 2, 3, 6-trimethylphenyl and polymers thereof. Polyphenylene ether (PPE) is also known as polyphenylene oxide (PPO) and is described in the literature. See U.S. Pat. Nos. 3,306,874, 3,306,875; 3,257,357; and 3,257,358, which are herein incorporated by reference.

Frequently polyphenylene ether materials are a blend of other thermoplastic or cross-linked ethylenically unsaturated materials such as polyolefinic materials, styrene or styrene butadiene or polyacryamide and the like. These materials are commercially available such as Noryl, Luranyl, Ultranyl or Vestoblend, trademarks of GE. Some materials that may be utilized include Noryl WCV072, WCV072L-111, and the like of GE.

It has been found that the ultra thin cable and cable wall that is utilized in the present case even at a small cross section of 0.1 mm² give a very satisfactory result in abrasion cycling tests such as that called for in ISO-6722.

The cross sectional area of the copper wire can range from about 0.1 to about 3 square millimeters, such as 26 AWG to 12 AWG, alternatively 0.13 to 1.5 square millimeters.

The insulated cable of the present invention is prepared utilizing normal well known commercially available equipment where the desired polyphenylene ether polymer is fed to an extrusion machine where the molten viscous polymer is passed through a die, as shown in FIGS. 3-4, so that the insulating PPE is wrapped around the linear portion of the metal conductor wire. The processing temperatures that may be utilized can vary as is well known in the industry. However, it has been found desirable to heat the resin material obtained from the supplier as follows. The thermoplastic polyphenylene ether material is dried at about 180° F. for at least 2 hours and is then passed through the first stage of an extrusion machine. The feed temperature is approximately 115° F. The compression temperature and the metering temperature in the barrels of the extruder can vary. A compression temperature may be from about 475° F. to 490° F. The metering temperature is approximately 500° F. to 540° F. The cross head or the die temperature is approximately 540° F. to 560° F. After the wire is extruded with the insulated material thereon, it passes through a cooling water bath and mist which is maintained at room temperature and then is packed as a cable in a barrel for subsequent handling.

Turning now to a description of the drawings. FIG. 1 is the insulated vehicular cable 10 of the present invention having an insulated member 12 of PPE extruded or wrapped around the copper base metal core 14. An embodiment is shown in FIGS. 1 and 2 wherein the inner copper core is comprised of several wires 14A-G with a central wire 14A. The central wire 14A is surrounded by the other wires 14B-G. There can be 7, 19 or 37 strands in metal core 14, in some instances they are compressed and in the other they are bunched.

During the extrusion process of the insulated vehicular cable 10, the copper based core is fed through the middle of die 20 entering the back end 22 of the die and exiting from the die at 24. The die has a central portion 26 through which the copper based wire 14 passes. The hot viscous PPE will be passed into the space 28 at the entrance end 22 of the die 20 and proceeds to envelop the copper wire. The die begins to narrow at 30 as PPE is extruded with the copper based wire passing from 30 through exit 24 of the die. At the exit 24 of the die, the insulated vehicular cable 10 of the present invention is obtained. The cooling process as described above and the packaging of the cable follows thereafter.

The diameter of the insulated vehicular cable 10 of the present invention can vary substantially. A cable diameter that has been found useful is between 0.85 and 0.92 mm in case of 0.13 mm² cable. Other dimensions of an insulated vehicular cable would be one that has approximately 0.13 square millimeters of wire as its cross sectional area but which is used to form the embodiment shown in FIG. 1 namely a central wire with six surrounding wires. In that case, the conductor diameter may be approximately 0.465 millimeters with a cable diameter 10 of approximately 0.88 millimeters with the minimum insulated wall thickness of 0.198 millimeters.

As indicated above a wide variety of commercially available extruding equipment may be utilized such as an extruder identified as BMD60-24D or a Nokia Maillefer, and the like.

Following the procedures outlined in ISO-6722, scrape abrasion resistance using 7(N) load and 0.45 millimeter needle was used on three sets of cables, the first being compressed halogen free cable ISO ultra thin wall cable referred as CHFUS, the second ISO thin wall cable referred as HFSS and the third ISO thick wall cable referred as HF. The test results are identified in tables 1 and 2 below.

TABLE 1 CHFUS 0.13* 0.22* 0.35* 0.50* 0.75* 1.00* 1.25* Normal Force(N) 4.0 4.0 5.0 5.0 6.0 6.0 6.0 Minimum cycles required 100 100 100 150 150 180 180 at the normal force Result 166 550 338 376 536 526 1315 7N Load 151 338 244 1150 836 960 2181 125 379 223 458 1078 1171 610 174 397 287 560 722 984 2673 Minimum cycles attained 125 338 223 376 536 526 610 by the cable at 7 Newton load Pass/Fail ∘ ∘ ∘ ∘ ∘ ∘ ∘ *Wire Size (square mm)

TABLE 2 HFSS HF 0.35* 0.50* 0.75* 1.00* 1.25* 2.00* 3.00* Normal Force(N) 5.0 5.0 6.0 6.0 6.0 7.0 7.0 Minimum cycles required 100 150 150 180 180 750 750 at the normal force Result 443 4067 7193 6043 10434 12586 *>5000 7N Load 2396 893 9636 3896 5158 10835 830 4271 4512 7771 3559 11203 1031 2586 6198 8776 16333 12308 Minimum cycles attained 443 893 4512 3896 3559 10835 *>5000 by the cable at 7 Newton load Pass/Fail ∘ ∘ ∘ ∘ ∘ ∘ ∘ *Wire Size (square mm)

Following the procedures outlined in ISO-6722 a number of tests were so performed where the cross sectional area of the copper wire varied as well as the diameter of insulated polyphyenelyene ether varied as is shown in tables 3-4.

TABLE 3 CHFUS Cable Type and Size Size Test Item Unit Wire Thickness Area (square mm) 0.13 0.22 0.35 0.50 ISO6722 Certifi- Dimensions Thickness of (mm) 0.179 0.274 0.190 0.211 cation Ins.(min) Cable Outer (mm) 0.872 1.027 1.127 1.279 Dia. Electrical Resistance (mΩ/m) Sec 6.1 Must be smaller than 157.100 78.600 49.600 34.600 requirement (Measured result) See Table 4 (mΩ/m) Requirement 169.900 84.400 54.400 37.100 Ins. Resistance Sec. 6.2 Breakdown shall not Pass Pass Pass Pass in water occur Spark test Sec. 6.3 No breakdown shall Pass Pass Pass Pass occur when the earthed cable is drawn through the test electrode Mechanical Pressure test Sec. 7.1 Breakdown shall not Pass Pass Pass Pass at high temp. occur during the withstand voltage test Low-temp Winding under Sec. 8.1 After winding, no Pass Pass Pass Pass low temp conductor shall be visible. During the withstand voltage test, breakdown shall not occur. Abrasion Scrape (N) Sec. 9.3 Load requirement 4 4 5 5 (times) Scrape requirement 100 100 100 150 (times) Min. scrape result 1309 3052 951 1636 Heat aging Short high Sec. 10.1 After winding, no Pass Pass Pass Pass temp conductor shall be visible. During the withstand voltage test, breakdown shall not occur. Long high Sec. 10.2 After winding, no Pass Pass Pass Pass temp 85 deg C. conductor shall be visible. During the withstand voltage test, breakdown shall not occur. Shrinkage by (mm) Sec. 10.4 The maximum shrinkage Pass Pass Pass Pass high temp shall not exceed 2 mm at either end Resistance Gasoline Sec. 11.1 The maximum outside Pass Pass Pass Pass to chemical (%) cable diameter change shall 5.15 5.40 0.09 2.83 Diesel meet the requirement shown in Pass Pass Pass Pass (%) Table 13. After winding, 4.56 4.72 8.63 −0.58 Engine Oil no conductor shall be visible. Pass Pass Pass Pass (%) During the withstand voltage 5.75 2.44 2.70 −6.91 test, breakdown shall not occur. CHFUS Size Test Item Unit 0.75 1.00 1.25 1.50 ISO6722 Certifi- Dimensions Thickness of (mm) 0.194 0.196 0.210 0.223 cation Ins.(min) Cable Outer (mm) 1.391 1.590 1.794 1.849 Dia. Electrical Resistance (mΩ/m) 24.300 17.200 14.100 12.000 (mΩ/m) 24.700 18.500 14.900 12.700 Ins. Resistance Pass Pass Pass Pass in water Spark test Pass Pass Pass Pass Mechanical Pressure test Pass Pass Pass Pass at high temp. Low-temp Winding under Pass Pass Pass Pass low temp Abrasion Scrape (N) 6 6 6 6 (times) 150 180 180 200 (times) 441 844 883 1058 Heat aging Short high Pass Pass Pass Pass temp Long high Pass Pass Pass Pass temp 85 deg C. Shrinkage by (mm) Pass Pass Pass Pass high temp Resistance Gasoline Pass Pass Pass Pass to chemical (%) −6.39 0.06 0.00 0.32 Diesel Pass pass Pass Pass (%) −0.40 6.20 3.55 1.88 Engine Oil Pass Pass Pass Pass (%) −5.66 −4.84 0.83 0.70

TABLE 3A CHFUS Cable Type and Size Size Test Item Unit Wire Thickness Area (square mm) 0.13 0.22 0.35 0.50 Flame Flamability at 45 (Sec) Sec. 12 Any combustion flame 0.0 0.0 0.0 0.0 degree angle of insulating material shall extinguish within 70 s, and a minimum of 50 mm of insulation at the top of the test sample shall remain unburned If Electrical Insulation volume Ohm mm Sec. 6.4 Greater than 10° Pass Pass Pass Pass required resistivity Ohm mm 1.6E+15 1.0E+16 1.70E+16 2.50E+21 Mechanical Strip force (N) Sec. 7.2 Greater than speci- 28.8 Pass 31.6 Pass 41 Pass 69.7 Pass fied by customer Requirement 2 2 5 5 (Min) Low-temp Impact Sec. 8.2 After impact, no Not Not Not Not conductor shall be visible. required required required required During the withstand voltage test, breakdown shall not occur. Heal aging Thermal overload Sec. 10.3 After winding, no Pass Pass Pass Pass conductor shall be visible. During me withstand voltage, breakdown shall not occur Resistance Ethanol Sec. 11.1 The maximum outside Pass Pass Pass Pass to chemical (%) cable diameter change 4.01 4.42 2.70 −6.98 Power steering fluid shall meet the requirement Pass Pass Pass Pass (%) shown in Table 13. After 4.00 6.39 3.68 5.76 Automatic transmission winding, no conductor shall Pass Pass Pass Pass fluid (%) be visible. During the 4.07 5.52 4.31 6.05 Engine coolant withstand voltage test, Pass Pass Pass Pass (%) breakdown shall not occur. 3.09 0.29 0.99 1.65 Battery Pass Pass Pass Pass (%) −0.11 1.48 1.08 2.12 Ozone Sec. 11.3 The visual examination Pass of the insulation shall not reveal any cracks Hot water (Ω · mm) Sec. 11.4 The insulation Pass volume resistivity shall not be less than 10° Ohm mm. A visual examination of the insulation Temp. and humidity Sec. 11.5 After winding, no Pass Pass Pass Pass cycling conductor shall be visible. During the withstand voltage test, breakdown shall not occur CHFUS Size Test Item Unit 0.75 1.00 1.25 1.50 Flame Flamability at 45 (Sec) 0.0 0.0 4.0 4.0 degree angle If Electrical Insulation volume Ohm mm Pass Pass Pass Pass required resistivity 8.60E+17 3.50E+21 7.30E+17 9.10E+19 Mechanical Strip force (N) 52.5 Pass 75.7 Pass 70.1 Pass 63.8 Pass 5 5 5 5 Low-temp Impact Not Not Not Not required required required required Heal aging Thermal overload Pass Pass Pass Pass Resistance Ethanol Pass Pass Pass Pass to chemical (%) −6.06 −5.26 1.33 1.61 Power steering fluid Pass Pass Pass Pass (%) −4.73 −3.48 1.33 3.71 Automatic transmission Pass Pass Pass Pass fluid (%) −2.46 −3.96 2.11 1.51 Engine coolant Pass Pass Pass Pass (%) −0.20 0.06 0.44 −0.32 Battery Pass Pass Pass Pass (%) −1.00 0.24 0.00 −0.32 Ozone Pass Hot water (Ω · mm) Pass Temp. and humidity Pass Pass Pass Pass cycling

TABLE 4 HFSS Cable Type and Size Size Test Item Unit Wire Thickness Area (square mm) 0.35 0.50 0.75 1.00 ISO6722 Certifi- Dimensions Thickness of (mm) 0.258 0.231 0.252 0.322 cation Ins.(min) Cable Outer (mm) 1.289 1.481 1.773 1.943 Dia. Electrical Resistance (mΩ/m) Sec 6.1 Must be smaller than 46.200 33.100 23.200 16.800 requirement (Measured result) See Table 4 (mΩ/m) Requirement 54.400 37.100 24.700 18.500 Ins. Resistance Sec. 6.2 Breakdown shall not Pass Pass Pass Pass in water occur Spark test Sec. 6.3 No breakdown shall Pass Pass Pass Pass occur when the earthed cable is drawn through the test electrode Mechanical Pressure test Sec. 7.1 Breakdown shall not Pass Pass Pass Pass at high temp. occur during the withstand voltage test Low-temp Winding under Sec. 8.1 After winding, no Pass Pass Pass Pass low temp conductor shall be visible. During the withstand voltage test, breakdown shall not occur. Abrasion Scrape (N) Sec. 9.3 Load requirement 5 5 6 6 (times) Scrape requirement 100 150 150 180 (times) Min. scrape result 1688 2141 >5000 >5000 Heat aging Short high Sec. 10.1 After winding, no Pass Pass Pass Pass temp conductor shall be visible. During the withstand voltage test breakdown shall not occur. Long high Sec. 10.2 After winding, no Pass Pass Pass Pass temp 85 conductor shall be visible. deg C. During the withstand voltage test, breakdown shall not occur. Shrinkage by (mm) Sec. 10.4 The maximum shrinkage Pass Pass Pass Pass high temp shall not exceed 2 mm at either end Resistance Gasoline Sec. 11.1 The maximum outside Pass Pass Pass Pass to chemical (%) cable diameter change shall −4.79 −4.54 −3.57 2.07 Diesel meet the requirement shown in Pass Pass Pass Pass (%) Table 13. After winding, −3.50 −2.71 −1.65 3.16 Engine Oil no conductor shall be visible. Pass Pass Pass Pass (%) During the withstand voltage −6.36 −5.74 1.17 2.19 test, breakdown shall not occur. HFSS PPO HF Size Size Test Item Unit 1.25 2.00 3.00 ISO6722 Certifi- Dimensions Thickness of (mm) 0.320 0.348 0.653 cation Ins.(min) Cable Outer (mm) 2.088 2.551 3.598 Dia. Electrical Resistance (mΩ/m) 13.900 8.840 5.76 (mΩ/m) 14.900 9.420 6.150 Ins. Resistance Pass Pass Pass in water Spark test Pass Pass Pass Mechanical Pressure test Pass Pass Pass at high temp. Low-temp Winding under Pass Pass Pass low temp Abrasion Scrape (N) 6 7 7 (times) 180 750 750 (times) >5000 10835 >5000 Heat aging Short high Pass Pass Pass temp Long high Pass Pass Pass temp 85 deg C. Shrinkage by (mm) Pass Pass Pass high temp Resistance Gasoline Pass Pass Pass to chemical (%) 2.23 6.77 13.4 Diesel Pass Pass Pass (%) −2.00 2.20 1.63 Engine Oil Pass Pass Pass (%) −3.91 0.94 0.14

TABLE 4A HFSS Cable Type and Size Size Test Item Unit Wire Thickness Area (square mm) 0.35 0.50 0.75 1.00 Flame Flamability at (Sec) Sec. 12 Any combustion flame 0.0 0.0 4.0 5.0 45 degree angle of insulating material shall extinguish within 70 s, and a minimum of 50 mm of insulation at the top of the test sample shall remain unburned If Electrical Insulation volume Ohm mm Sec. 6.4 Greater than 10° Ohm Pass Pass Pass Pass required resistivity mm 2.90E+21 7.70E+17 8.30E+16 2.80E+16 Mechanical Strip force (N) Sec. 7.2 Greater than speci- 63 Pass 115.3 69.4 Pass 88.0 Pass fied by customer Requirement 5 5 5 5 (Min) Low-temp Impact Sec. 8.2 After impact, no Not Not Pass Pass conductor shall be visible. required required During the withstand voltage test, breakdown shall not occur. Heat aging Thermal overload Sec. 10.3 After winding, no Pass Pass Pass Pass conductor shall be visible. During the withstand voltage, breakdown shall not occur Resistance Ethanol Sec. 11.1 The maximum outside Pass Pass Pass Pass to chemical (%) cable diameter change shall 5.93 −5.36 1.17 5.97 Power steering fluid meet the requirement shown Pass Pass Pass Pass (%) in Table 13. After winding, −5.36 −3.72 −3.52 6.99 Automatic transmission no conductor shall be visible. Pass Pass Pass Pass fluid (%) During the withstand voltage −5.65 −4.61 −3.09 6.99 Engine coolant test, breakdown shall not occur. Pass Pass Pass Pass (%) −7.22 0.13 −5.54 −1.17 Battery Pass Pass Pass Pass (%) 0.78 −0.19 −0.32 5.00 Ozone Sec. 11.3 The visual examination Pass of the insulation shall not reveal any cracks Hot water (Ω · mm) Sec. 11.4 The insulation volume Pass resistivity shall not be less than 10° Ohm mm. A visual examination of the insulation Temp. and humidity Sec. 11.5 After winding, no Pass Pass Pass Pass cycling conductor shall be visible. During the withstand voltage test, breakdown shall not occur HFSS PPO HF Size Size Test Item Unit 1.25 2.00 3.00 Flame Flamability at (Sec) 4.0 8.0 14 45 degree angle If Electrical Insulation volume Ohm mm Pass Pass Pass required resistivity 3.20E+16 9.70E+16 3.40E+21 Mechanical Strip force (N) 112 Pass 113.3 Pass 230 5 10 15 Low-temp Impact Pass Pass Pass Heat aging Thermal overload Pass Pass Pass Resistance Ethanol Pass Pass Pass to chemical (%) −3.82 1.45 1.3 Power steering fluid Pass Pass Pass (%) −2.64 2.08 0.36 Automatic transmission Pass Pass Pass fluid (%) −2.55 1.92 0.58 Engine coolant Pass Pass Pass (%) 0.00 0.74 0.64 Battery Pass Pass Pass (%) 0.38 −0.04 0 Ozone Pass Hot water (Ω · mm) Pass Temp. and humidity Pass Pass Pass cycling

While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all of the possible equivalent forms or ramifications of the invention. It is understood that the terms used herein are merely descriptive rather than limiting and that various changes may be made without departing from the spirit or the scope of the invention. 

1. An insulated non-halogenated, heavy metal free vehicular cable comprising: an inner core of a copper based metal wire having a cross sectional area of about 0.1 mm² to 0.13 mm², an outer insulation, covering the length of the inner core, comprised of a thermoplastic polyphenylene ether composition that has no halogen or heavy metal added thereto, wherein the polyphenylene ether comprises a polymer formed from an ethylenically unsaturated material, the insulation having improved abrasion resistance, and wherein the insulated cable is constructed and arranged to withstand flame at a 45 degree angle such that any combustion flame of the outer insulation extinguishes within 70 seconds and a minimum of 50 mm of insulation at the top of the insulated cable remains unburned, and to have a scrape abrasion resistance of greater than 100 cycles using a 7N load and a 0.45 millimeter needle.
 2. The insulated cable of claim 1 in the form of an automotive wire harness.
 3. The insulated cable of claim 1 wherein the inner core of the copper based metal wire has a cross sectional area of 0.13 mm².
 4. The insulated cable of claim 1 wherein the ethylenically unsaturated material comprises an olefinically unsaturated material.
 5. The insulated cable of claim 1 wherein the ethylenically unsaturated material comprises a styrene butadiene material. 